@article {Aitken:2005:1061-4303:3019,
author = "Aitken, Michael D and Walters, Glenn W and Crunk, Phillip L and Willis, John L and Farrell, Joseph B and Schafer, Perry L and Arnett, Cliff and Turner, Billy G",
title = "Laboratory Evaluation of Thermophilic-Anaerobic Digestion to Produce Class A Biosolids. 1. Stabilization Performance of a Continuous-Flow Reactor at Low Residence Time",
journal = "Water Environment Research",
volume = "77",
number = "7",
year = "2005",
publication date ="2005-11-01T00:00:00",
abstract = "There is increasing interest in the United States in producing biosolids from municipal wastewater treatment that meet the criteria for Class A designation established by the U.S. Environmental Protection Agency. Class A biosolids are intended to be free of pathogens and also must meet
requirements for reduction of the vector-attraction potential associated with untreated sludge. High-temperature processes are considered to produce Class A biosolids if the combination of operating temperature and treatment time exceeds minimum criteria, but this option is not applicable
to mixed, continuous-flow reactors. Such reactors, or any combination of reactors that does not meet the holding time requirement at a specific temperature, must be demonstrated to inactivate pathogens to levels consistent with the Class A criteria. This study was designed to evaluate pathogen
inactivation by thermophilic anaerobic digestion in a mixed, continuous-flow reactor followed by batch or plug-flow treatment. In this first of a two-part series, we describe the performance of a continuous-flow laboratory reactor with respect to physical and chemical operating parameters;
microbial inactivation in the combined continuous-flow and batch treatment system is described in the second part. Sludges from three different sources were treated at 53\textdegreeC, while sludge from one of the sources was also treated at 55 and 51 \textdegreeC. Relatively short hydraulic retention
times (four to six days) were used to represent a conservative operating condition with respect to pathogen inactivation. Treatment of a fermented primary sludge led to an average volatile-solids (VS) destruction efficiency of 45%, while VS destruction for the other two sources was
near or below 38%, the Class A criterion for vector attraction reduction. Consistent with other studies on thermophilic anaerobic digestion of sludges at short residence times, effluent concentrations of volatile fatty acids (VFAs) were relatively high. Also consistent with other studies,
the most abundant VFA in the effluent was propionate. Gas production ranged from 0.3 to 0.5 m3/kg VS fed and from 0.8 to 1.3 m3/kg VS destroyed.",
pages = "3019-3027",
itemtype = "ARTICLE",
parent_itemid = "infobike://wef/wer",
issn = "1061-4303",
eissn = "1554-7531",
publishercode ="wef",
url = "http://www.ingentaconnect.com/content/wef/wer/2005/00000077/00000007/art00006",
doi = "doi:10.2175/106143005X73901",
keyword = "biosolids, sludge stabilization, thermophilic-anaerobic digestion, Class A, land application"
}